Head gasket thickness? Effect on comp. ratio?

[Cali HP Addict]

Can any of you motorheads tell me the compressed thickness of a stock head gasket? Fel-Pro? I know the Cometic is .030 but I think that is thinner than stock. How much is the compression ratio affected by say a .015 difference in head gasket thickness?

 

[MikeVistaBlue06]

Please tell me the volume of the combustion chamber, usually in cc's and I can give you an exact answer. In the mean time I will calculate a first order approximation.

Mike

 

[94tbird]

Combustion chamber Volume 48.1-51.1 cc (2.94-3.12 cu in)

 

[MikeVistaBlue06]

Assumptions: Stock gasket is 0.030" and stock CR is 9.8:1

Dropping the gasket thickness by 0.015" will bump your CR to ~10.2:1 (10.19 is what I got)--this excludes the combustion chamber volume. However I just saw that was posted so I will go re-run the numbers for you.

No math is shown, but I can sure show it if ya wanna see it!

Mike

 

[MikeVistaBlue06]

Ok, here is the best answer I can give you:

Assumptions: Original gasket thickness is 0.030", stock compression ratio is 9.8:1, and combustion chamber volume is 50cc.

Dropping the gasket thickness by 0.015" will bump the CR to 10.16:1

Thanks Ron for the combustion chamber data!

Also, if you need me to start with a different thickness head gasket just let me know what it is, and then how much to reduce it by, and I can give you those numbers as well.

I found this on the web as well: http://www.rbracing-rsr.com/compstaticcalc.html

I don't know the values for some of the things they list in the calculator.

Hope this helps.

Mike

 

[spyder7724]

don't forget that changing the deck height/gasket thickness will affect cam timing on mod motors. usually it retards the cams and puts slack in the chain.

 

[Cali HP Addict]

I am running a stroker motor with CNC machined heads. I cannot tell you what the head cc is but it is supposidly 9.8-1 (stock) compression ratio with stock gaskets. I am sure you are correct that the stockers are .030 thick and I am thinking of running some SCE ICS Titan copper gaskets which are .043" thick. So what would be the affect on C.R. and cam timing by adding .013 thickness to the gaskets?
BTW, you guys rock!

 

[MikeVistaBlue06]

I am running a stroker motor with CNC machined heads. I cannot tell you what the head cc is but it is supposidly 9.8-1 (stock) compression ratio with stock gaskets. I am sure you are correct that the stockers are .030 thick and I am thinking of running some SCE ICS Titan copper gaskets which are .043" thick. So what would be the affect on C.R. and cam timing by adding .013 thickness to the gaskets?
BTW, you guys rock!

I can't say what the change in timing will be, but using the same numbers I did to get the 10.16:1 ratio, if you start with a gasket that is 0.030" thick and add 0.013", your compression ratio will drop from 9.8:1 to 9.44:1.

Hope this helps.

Mike